Preparation of alcoholic derivatives of olefine-bearing substances



Jan. 27, 1931.

H.` s. DAvls PREPARATION 0F' .-ALCOHOLIC DERIVATIVES OF OLEFINE BEARING SUBSTANCES Filed July 1s, 1925 '2 sheets-sheet 1 kum.

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PREPARATION OF ALCOHOLIC DERIVATIVES OF OLEFINE BEARING SUBSTANCES Filed July 15,. 1925 2 Sheets-Sheet 2 Poly/77er Z5? 72205' ffl/5:

Patented Jan. 27, 1931 UNITED. ,STATES PATENT-OFFICE HAROLD s. DAvIs, OE BELMONT, MAss'AOHUsETTs, AssIGNoa, EY MEsNE ASSIGN- MENTS, To PETROLEUM CHEMICAL CORPORATION, OE NEW YORK, N. Y., A con- PORATION 0F DELAWARE PREPARATION 0F ALCOHOLIC DERIVATIVES OF OI'JEIEINE-BEARINGl SUBASTANCES Application` led July 13, 1925. Serial No. 43,208.

This invention provides a process for the preparation of alcohols, including secondary and tertiary alcohols of olefine hydrocarbons, from the results of heat treatment of such source materials as petroleum, peat, coal, oil

shales and like organic substances. This process is applicable to the treatment of mixed olefine-bearing hydrocarbons resulting from as complete generation by heat treatment of olefine hydrocarbons -as possible.

The process of the present invention is particularly usefulfor the recovery of alcohols from any hydrocarbon'` mixture containing oletines, and especially useful when the mixture ,treated contains butylenes, amyl'enes and he`xylenes as major constituents.

A natural hydrocarbon material having been subjected to a regulated vapor phase cracking suitable for the production of Oleine-bearing gases, the gaseous and vaporous eilux is thensubjected to fractionation by condensation, or distillation, or both, whereby the light normally condensible or liquid hydrocarbons, including amylenes-and hexylenes, are segregated into one fraction, preferably with a distillation end-point ofl C. .In this fraction, hereinafter mentioned for lconvenience as an amylene fraction, may also be absorbed the butylenes, of which there are three,

Isobutene Boiling point-6 C. Butene-Q Boiling point+1 C. Butene-l Boiling point-59 C.

or the butylene contents may be' segregated and separatelytreated for the recovery of butyl alcohols.

While a principal industrial value of the present process lies in the facility afforded by it for the treatment of the mixed amylene and butylene fraction referred to for the recovery of amyl,"butyl and hexylV or higher alcohols, I am not to `be understood as restricting the invention claimed to treatment of this particular mixture, since this invention comprises a series of steps primarily useful for the recovery of tertiary and secondary alcohols from mixtures resulting from the heat treatment of hydrocarbons, or otherwise formed. when the said mixtures contain series of olefine materials capable of conversion into alcohols. Objects of the invention include the provision of steps suitable to the treatment of the said materials, or any of them severally, to obtain alcoholic derivatives.

A The preferred light normallyY liquid hydrocarbon material to be treated, as referred to above, is characteristically composed almost wholly of unsaturated hydrocarbons which conveniently may beclassified in three principal groups.

(l) Dienestdiolefines) such as butadiene and isoprene;

(2) Iso-oletines which yield tertiary derivatives;

(3) Olefines bot-h isoandnormal which yield secondary derivatives.

The preferred material segregated .for the treatment to be described is substantially stripped of propylene, ethylene and other gases resulting from the heat treatment. But the presence, accidental or intentional, of other Olefnes, propylene and ethylene, or

Vother more inert gases, is not detrimental to this process. The relatix'e amounts of the individual components may vary in this unsaturated hydrocarbon mixture Without necessarily involving any desirable change in the sequence of steps herein recommended. v

For example, beginning with the preferred vapor phase cracking process as a point of origin, it is optional Whether the butylenes are caused to be absorbed entirely into the amylene fraction which necessitates treat lnent under slight pressure), or Whether a fraction containing only a part Aof the butylenes resulting from pyrogenesis is subjected to treatment. It is not necessary to advantageous practice that the fraction treated shall contain no h drocarbons above the hexylenes in molecu ar wei ht, where alcohols above hexyl are desire a wider range of hydrocarbons may be treated. Mixtures containing other substances than the mentioned groups may advantageously be treated when suiiiciently rich in the materials of said grou or any of them. a

I lisave discovered that the isololeflnes which yield tertiary alcohols are capable of being selectively converted and the alcohol recovered with a minimum of acid consumption. I have discovered that those iso-olefines which yield tertiary alcohols, hereinafter referred to as tertiary base olefines, can be completely and selectively separated from the secondary base olefines with direct conversion into tertiary alcohols by the use of acid preferably sulfuric under carefully regulated conditions, and this step exemplifies the first stage of this process.

In practice I have found that the selective .conversion into alcohols ofthe tertiary base oleiines can effectively be achieved by the use of sulfuric acid of a concentration at or near at normal temperatures, though I prefer to use acid, which is more reactive and accomplishes the desired conversion in a shorter time, in eneral, I may employ for this purpose sulp uric acid of not exceeding concentration. A

In the second stage of this process, second'- ary alcohols are produced by reacting on the hydrocarbon material, residual from thefirst stage, under different conditions and preferably with stronger acids. As a step between these two stages, iit may sometimes be found desirable and advantageous to rectify the hydrocarbon mixture to separate therefrom the polymers produced in the first stage, and also to separate and recover an tertiary alcohols which may be preferential y dissolved in the hydrocarbon residues as an incidentof the conversion of the tertiary base olefines and as a consequence of their limited solubility in the dilute acid used in the first stage and their solubility in the unchanged hydrocarbons br the said polymers.

The strength of acid best adapted to react with the secondary base ole-fines depends Aupon the conditions of temperature, the presence of hydrocarbon diluents, and somewhat upon the proportions of the individual olefines comprising the mixture. In general, it

is found desirable successively to treat withv portions of acids, which may be of dilerent concentrations, with intermediate separation of the acid products, as by settling and decantation. .In general I find it advisable to sulphate the secondary base olefines by treatment with sulphuric acid of a concentration greater than 70%, and I also find it advisable ,to operate at temperatures above 30 C. In

my usual practice, I first treat with 77% acid in two successive portions, with intermediate separation, and then complete the reaction on the secondary base olelines with acid ofl a higher concentration. I have discovered that it is not essential to maintain temperatures below 30 C. in the second stage of this'process, and, in fact, that it is undesirable to do so. More complete recoveries of secondary alcohols can be realized by allowing the temperaturesto rise at this stage above 30 C.; in practice I prefer and recommend carryingcn the acid treatment at temperatures above 35 C. and below 45 C. The temperature may be allowed to rise still further in some cases.

But I advocate and recommend reaction on materials maintained in the liquid state, andtherefore-rec'ommend reaction under conditions of suitable pressure, especially when the temperature i's relatively high. Carrying out the acid reaction under light pressure contributes to the efficiency of conversion to alcohols.

The invention will now be described in relation to a typical instance of practice upon raw material comprising butylenes, amylenes and hexylenes in admixture with diolefines and other hydrocarbons, such as the s0- called amylene fraction mentloned above and in the said application Serial No. 10,992; but the treatment to be described is suitable without change for the normally condensible products of any cracking process when carried out upon the fractlon distilling u to 60 C., with or without all of the buty ene which can be condensed in this fraction by compression. 'lhe process will be described in connection with apparatus shown diagrammatically in the accompanying drawings, in which: y

Fig. l is a diagram and flow sheet in elevation; and

Fig. 2 isl a similar diagram illustrating further'treatment. f

Referring now to Fig. 1, hydrocarbon ma- `terial to be treated stored in a tank 1 is delivered in measured quantity through the pipe 2 into a treatment vessel 3, provided with agitating means such as the circulation pipe 4, pump 5, and spray pipe 6. Treater 3 is provided lwith 'a heating or cooling coil 7 for water, brine orrsteam circulation, and is suitably jacketed at 3* for heating, and should be capable of withstanding considerable pressur v 'n The material is now subjected toa first treatment for conversion of the tertiary base -contents into tertiary alcohols. To an initial charge of 100 volumes of h drocarbon material for a specific instance of7 of a typical amylene fraction in treater 3, 8.3 volumes of 65% sulfuric acid, for exam-- ple', maybe added from an acid tank 8 of a series of acid tanks 8, 9, 10, suitably comtreatment municating with treater 3 by valved connections to a pipe 11, at a rate which, according to temperatures as shown by the thermometer at 12, preferably does not result in a risel of temperature beyond 20 C. During the first period of this operation a slight temperature rise is practically unavoidable, and in case the charge is under pressure at the start, as in the instance where all or a considerable part of the available butylenes are present, a marked rise of pressure may take pipe 14 at a later period, as during treatment with a second charge of 65% acid mentioned below.

The time of the first treatment with sul- :Enric acid may vary with the material undergoing treatment and the degree in which agitation in treater 3 mixes the material and vthe acid, but usually the treatment is complete within a period of one and a half to two and a halt' hours, as'may be ascertained by .taking samples at iifteen-minute intervals from a tap 15, and determining the specific gravity of the settled acid layer. lVhen the gravity of the acid product falls to a substantially constant figure, the treatment is stopped; continuing beyond this point results in a lower recovery of tertiary alcohols. This is a general rule for all acid treatments as hereinafter specified; y

In the speciiic example relied upon as a typical instance throughout this description, the lirst treatment was completed in 90 minutes, and yielded, after stopping the circulating pump and allowing the mixture to settle for lifteen minutes to'stratify the acid product and hydrocarbon material, seventeen Volumes of acid product, speciiic gravity 1.17. It will'be understood that continuous testing may b'e dispensed with when the material, temperatures, pressures and acid concentrations are standardized, reliance uponcontrol of the time then producing the desired results.

The acid product only of this first or teri tiary-recovery treatment, which product/readily separates .from the unchanged hydrocarbon and polymer by gravity, is drawn off from the bottom of treater 3 through a pipe 16 into a storage tank 17, which may be providedwith a cooling-fluid circulation coil 17 a and thence, without delay during which the somewhat unstable acid product might deteriorate, passes into a neutralizer 18, which may be any suitable tank provided With agitating means 18a, and which previously has beencharged with milk-of-limel from a slaking tank 19 in amount predetermined by the acid content of the acid product batch in 17. Instead of milk-oflime other alkalies maybe used. It is desirable to equip the neutralizer 18 with a Water jacket 18" or with cooling coils, not shown, or otherwise to maintain in it a temperature below 35 C.; for example by admitting diluent very cold water by pipe 17. The tank 18 may be vented tofa condenser, not shown, in order to save any tertiary-alcohols that may be distilled over in consequence of a temperature rise attending neutralization.

In case the tertiary product is mainly or principally a butylene derivative, or when the recovery of tertiary amyl alcohol is not desired, the neutralization step may be dispensed with and distillationeffected from the diluted'acid product.

Immediately following the discharge of the tirst lot ot' acid product from treater 3, a similar series of operations on the residual hydrocarbons is carried out, using a second and usually an equal quantity ofjthe same acid, (e. g. 65% acid from tank 8 in the described instance). 'In the specific example, the second treat with 8.3 volumes of (35% acid yielded 10 volumes of acid product. This acid product is also drawn off into tank 17 and neutralizing tank 18 and neutralized with lime or an alkali. The neutralized product is now distilled.

The stirrer 18 is kept in operation while the acid product from 17 is run into tank 18, and while feeding a fractionating column 20, preferably of the bubble plate type, through feed pump 21 and line 22. The column 20 is operated as a-steam still by injecting steam at 23. The vapors of mixed tertiary alcohols pass overhead through line 24 to dephlegmator or reflux condenser 25, which canbe so regulated as to maintain any desired reflux ratio, returning its condensate through reflux leg 26 to the top plate of tower 20. The acid sludge or neutralization product may flow off from the bottom ot' tower 20 at 202 From condenser 25 the uncondensed vapors pass to condenser 27 discharging into separator 28, where two layers appear, a hydrocarbon layer, comprising unchanged hydrocarbons extracted by the acid, polymers and alcohols; and a water layer which contains substantially all of the tertiary butyl alcohol.

The hydrocarbon layer is drawn off through 29 into washer 30, of any design appropriate to effect intimate contact between water and the alcoholic content of liquids received, and to permit stratilication under gravity. In this washer the alcohol content is extracted with water injected at 31. The water-alcohol layer from 30 is discharged continuously through line 32, joining the water-alcohol stream from the separator 28 and layer, now substantially alcohol-free, is run ofifl through pipe 34 to the storage tank T, also shown in Fig. 2.

In one aspect of this invention, the first stage of treatment above described is valuable in a subtractive sense as a step for the selective removal from the mixture treated of the highly reactive unsaturated substances, including the tertiary base substances, leaving the A secondary base substances in an optimum state for reaction to valuable derivatives of these secondary basel substances. In this aspect, the particular steps performed for the selective removal of the tertiary base substances and the detrimental highly reactive substances are not essential to the process, and any competent treatment for the removal of the tcritary base materials may be substituted within this invention.

For example, where the production of the tertiary alcohols with the aid of sulfuric acid is not desired, the first stage of this process may with advantage be practised by the conversion of tertiary ba'se oleines into chlorides by reaction with concentrated hydrochloric acid, with subsequent extraction of the reaction products with water, resulting in the direct hydrolysis of the tertiarychlorides and their separation as dilute solutions of alcohols. In the broader aspects of my invention it is immaterial whether the hydrolysis of the acid reaction product of the tertiary base olefines or the acid reaction product of the secondary base olefines be achieved by dilution as in the hydrochloric acid treatment of the tertiary base reaction product or by neutralization with alkali and resultant dilution in the sulfuric acid'treatment of the tertiary base product. In any event, a certain amount of hydrolysis of the tertiary or secondary base olefines into tertiary or secondary base alcohols takes place during the acid treatment without otherwise causing it by dilution or neutralization. Following the hydrochlorination or other removal step, the remaining hydrocarbons may be treated according to the second stage of the process of the present invention about to be described to prepare therefrom secondary alcohols.

The hydrocarbon residual material is Vnow treated to form the acid absorption products of the .secondary-base-structure. olefines.

Returning now to the charge remaining in the treater 3, it is optional whether this shall be distilled to separate from the secondary base olefines any alcohols extracted from the acid product in the two preceding treatments with acid, and to separate polymers formed from the dioletines; or shall be subjected directly to the secondstage of the process for recovery of secondary alcohols. In this secondary stage successive extractions with acid of one concentration may be resorted to, though I prefer to employ two concentrathe start.

portions of sulfuric acid of 77% concentration, followed by one treatment with sul- :'furic acid of 86% concentration; .but acid diluted to may be used in the first treatment and acid as strong as in the last treatment, if some losses of ultimate alcohol may be tolerated.

A On the unit basis of volumesof hydrocarbons at the start of stage one, the first extraction in stage two may be made with thirteen volumes of 77% acid fed to the treater from acid tank 9 through pipe 11. The acid may be added over a period of fifteen minutes with circulating pump 5 in action from The temperature recorded at 12 shouldbe between 35 and 40 C.; if necessary to attain this temperature, steam may be admitted into coils 7 or acket 3, or both. The treatment is continued until acid product settled from samples taken at 15 shows `a minimum specific gravity; for example 1.29 in the specific instance. At the end of the treatment the circulating pump is shut oft', the mixture allowed to stratify intotwo distinct layers, and the acid product discharged from the bottom of treater 3 into a dilution tank 36 partly filled with water and fitted with cooling fluid circulation coils 37 and stirrer 38, which is operated during the dilution period. Instead of allowing the material to stratify in treater 3, it may, within the invention, be run ofl' into a suitable centrifugal separator, not shown, with some advantage in the completeness of separation and in the time required for separation. The hydrocarbon, in this case, is returned to treater 3, and the acid product delivered into dilution tank 36.

The degree to which the acid'product must be diluted to substantially avoid reversion to secondary base olefines and formation of derivatives of the alcohols, such as ethers, mayhave a limit as high as a 30% acid concentration when the distillation about to be' described, is conducted at substantially atp mosphericpressure, but I prefer to dilute to an acid concentration of 25%. In vacuo-distillation, lower degrees of dilution are permissible, the exact degree depending upon the vacuum employed; and, if distilled under pressure, higher dilutions should be used. Having treated with acid and run off the acid absorption product, the next of the several acid treatments referred to may be carried out in the same way on the residual hydrocarbon left in treater 3.

In practice upon the preferred material above mentioned the treatment comprises polymers, referrin agitation with a second portion of 13 volumes of 77% acid, and to follow this a treatment with 10 volumes of 86% acid run in from acid tank 10. The acid and aqueous separate, on settling as before, is diluted in tank 36 to convert the acid absorption product not already hydrolyzed into the secondary alcohols and to avoid spontaneous reversion to their bases or derivatives.

The dilution products are fed severally as they are made (with intervening mixture together, if desired) into a steam still 39, which may be of the bubble plate type. It is satisfactory to pump the dilution products severally through pipe 41 by a pump 40 into the still 39, to which steam is admitted at the bottom through connection 42, and from which exhausted dilute acid is drawn off through pipe 43 into storage, from which it may be drawn to a concentrating unit, not

shown, and brought into condition for reuse. From the top plate of the column still 39, the vapors pass throughpipe 44 to a reflux condenser 45, which can be regulated to maintain any desired reflux ratio, returning to the top plate through reflux leg 46. The uncondensedvapors are condensed at 47 and separated yat 48, the water-alcohol layer being returned to an intermediate plate in tower 39 through a pipe line 49. YThe hydrocarbon-alcohol layer, which may include some unchanged hydrocarbon in the boiling -ran e of the material in feed-tank 1 and sun ry polymers, is collected in ,tankv 50. This crude product is now to be refined.

As a first step in refining the crude alcohols collected at 50, the crude mixture may be fractionated in a column 51, dephlegmator 52, and condenser. 53, to separate the light hydrocarbons and return them through storage 54 and line 55 to hydrocarbon storage at 1. The mixed alcohol and heavy-hydrocarbon fraction is taken oil' at the bottom of column 51 through pipey 57 to a collection tank 56, and is now ready for refining.

The residual hydrocarbons remaining in treater 3 may now-be washed with water and residual traces of acid neutralized with caustic soda, and then distilled to separate therefrom the unchanged fraction, for example boiling up to an initial point at C. This residue containsv material, including high boilin polymers, distilling between 60 and 225 which is a. valuable motor fuel, and may be collected for this use.

The residual unaltered hydrocarbons and now to Fig. 2, which have been collecte in the tank T may be subjected to a fractionating treatment for the purpose of separating the fraction distilling to an end-point of 60 C., for re-treatment, preparing a fraction having a boilmg point range of from 60 C. to 225 C. for motor fuel use, and collecting the volatile l polymer boiling above 225 for use as flota t-ion oils, a source of synthetic'gums, and other useful products. The neutralized residue from the treater 3 may be delivered to the storare tank T through pipe 61, and the combinedu hydrocarbon residues there collected may be delivered .through pipe 62 into a refining still 63 fitted with a fractionating column 64, dephlegmator 65 and condenser 66. The temperature at the top of the column 64 is regulated for the desired end-point of the overhead' fraction, inv this case 60 C. This fraction may be returned to feed tank 1. The bottoms which collectI in still 63 may bepumped through line 67 into column 68, into which steam is injected at the base through inlet 69. By regulating the amount and temperature of the steam with referenceto the rate of feed through pipe 67, the der' sired end-point for the overhead fractionY from' column 68 can be maintained. The

run-back from the column 68 through pipe tor fuel may be drawn olf respectively at 73 and 74.

As a result of the foregoing operations the crude tertiary alcohols are recovered substantially unmixed with secondary alcohols, and conversely the crude secondar alcohols are substantially free from tertlary alcohols. The process is highly advantageous in respect to theA comparative volumes of alcohols recovered from the olefine material, and in respect to the requisite consumption of acid re1. atively tothe quantitative recovery of alcohols. In the specific instance described, when the process was carried out upon the volumes of mixed hydrocarbons, 64.5% of this material distilled below 60C. upon treatment there were recovered as alcohols 5.2 volumes of tertiaries and 19.1 volumes of secondaries; in terms of relative volume of the fraction boiling at 60 C. end-point, these extraction at 30 (Fig. 1) and can readily be separated into tertiary amyl and tertiary butyl alcohol (tri-methyl car inol) when` anhydrous, byv fractional distillation. The rocedure, 1n. rief, involves dehydration oA the 60-90 C .Mixed material; dry, and re-run with succeeding lot of crude alcohol. 90-100 --Crude secondary butyls.

- 110-125 ..Crude secondary amyls.

125-150 Crude secondary hexyls. Residues Hydrocarbons; returned to T,

Fig. 2.

-The resulting crude separates ofbutyl, amyl,

hexyl and heptyl alcohols lnay be refractionated, as will be obvious to those skilled in the art of rectifying alcohols, and otherwise treated to obtain alcohols of any desired degree of refinement. Preferred and recommended refinement treatments, which may be greatly varied, are no part of the present invention.

I do not herein claim the process for the preparation of tertiary alcohols, which is the subject of my divisional application, Serial No. 170,632, filed February 24, 1927.

I lclaim:V

1. The rocess of converting the butylenes of cracked) petroleum into secondary and tertiary alcohol which consists in absorbing the butylenes under pressure into a mixture of liquid olefines boiling under 100 C., and treating the mixture under pressure with sulfuric` acid of approximately sixty-live per eentum concentration while maintaining the temperature below 30 C., and then treating with acid of a concentration above seventy per centum and allowing the temperature to rise to between 35 and 45 C. L

2. Process for the preparation of derivatives of mixed hydrocarbons in a liquid state containing tertiary base olefines and secondary base olefines comprising selectively sulphating the tertiary base olefines by treat-` .ment with `sulfuric acid at a concentration not exceeding 65% and' a temperature not in excess of 30 C., removing the sulphated tertiary base olefines and thereafter sulphati'ng the secondary base olefines by treatment with sulfuric acid between and 95% at temperatures between 30 and 45 C.

3. Prbcess of'sulphating secondary olelincs of not exceeding 6 carbon atoms to the molecule in a mixture of hydrocarbons 'derived from the pyrolysis of petroleum oil co'n'tain ing olefines, vsaid olefines consisting predominantly of secondary and tertiary olelines of not exceeding, 6 carbon atoms to theV molecule,.which com rises selectively removing the tertiary ole nes from said mixture, and thereafter sulphating at least a part of the said secondary olefinesby admixing the ing the said mixture with aqueous sulphuric l acid of not exceeding 65%, HzSO., content, at temperatures not exceeding 20 C.

6. Process according to claim 3, in which the sulphation of the said secondary olefines is accomplished by admixing the same with sulphuric acid of from 7 0 to 95%, H2SO4 content, while maintaining a temperature at which sulphation of the said secondary olelines takes place.

7. Process according to claim 3, in which the sulphation of the said secondary olefines is accomplished by admixing the same with sulphuric acid of from 70 to 95%. H2804 con- A tent, at temperatures between 30 and 45 C.

8. Process of sulphating secondary olefines 'of not exceeding 6 carbon atoms to the molecule occurring in a mixture of hydrocarbons derived from the pyrolysis of petroleum oil containing olefines, said olefines consisting predominantly of secondary and tertiary olefines of not exceeding 6 carbon atoms to the molecule, which comprises separating from said mixture by distillation a fraction, the oleiine content of which fraction consists predominantly of olefines of from 4 to 6 carbon atoms to the molecule, selectively removing thetertiary olefines from said fraction. and thereafter sulphating at least a partof the said secondary olefines by admixing the same with aqueous sulphuric acid while maintaining an acid concentration and a temperature at 4which sulphation of said secondary olefines takes place.

9. Process according to claim 8, in which the selective removal of the tertiary olelines from said mixture is .accomplished by admixing the said mixture with aqueous sulphuric acid of not exceeding70%, H2SO4 content, while maintaining a temperature below that at whichsubstantial amounts of said secondis accomplished by admxing the sume with sulphur-ic acid of from 7 0 to 95%, HZSO, content, while maintaining a temperature at which sulphation of the said secondary olefines takes place. 12. Processv according to claim 8, in whichv the vsulphation ofthe said secondary olenes is accomplished b admixing the same with sulphuric acid of rom 70 to 95%, HQSO, content, at temperatures between 30 and 45 C. Signed by me at Bosto, Massachusetts,

July, 1925.

s HAROLD S. DAVIS. 

